Formation of oxynitride as the photocatalytic enhancing site in nitrogen-doped titania nanocatalysts: Comparison to a commercial nanopowder

A nitrogen doped TiO2 nancolloid has been successfully prepared and it's properties compared with the commercially available TiO2 nanomaterial, Degussa P25. Several characterization techniques, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) transmission electron spectroscopy (TEM), Fourier transform infrared (FTIR) spectroscopy. Raman scattering and UV visible reflectance spectra are combined in order to determine the crystal phase and grain size, shape, degree of nitrogen incorporation and nature of the resultant oxynitride chemical bonding on the surface and in the bulk. The high relative photocatalytic activity of the nitrogen doped-TiO2 nanocolloid is evaluated through the study of the decomposition of methylene blue under visible light excitation. The ease and degree of substitutional insertional nitrogen doping is held accountable for the significant increase in photocatalytic activity in the porous nanocolloid versus the nitrided comercial nanopowder. It is suggested that the nitrogen incorporation produces an NO bonding region as evidenced by the resulting XPS spectrum.